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[on:]

  I'd like to start yet another rehash of DIY Arduino.  This time with a pcb that is within 5cmx5cm size so that iteadstudio will build it for $1.40 in packs of 10.

  The actual shield size is a fraction of an inch bigger so female headers bend just slightly.

  You will need an atmega328 or atmega168 with bootloader flashed, and a CP2102 which is a $3.00 (ebay) usb to serial converter, which has been slightly modified to connect dtr to reset line.

  Actual cost is about $7.00:  pcb: $1.4, atmega328: $3.30, other parts about $2.00

  Here is a video
  

    Schematic, Board and Gerber files: http://atmega.site40.net/default.php?bookmark=ArduinoDIY

  It also has optional breakouts for an nrf24l01 so that it can be used for home automation

[Reply #1 on:]

Pretty nice!

Your projects seem to consistently use those 2-termial ceramic resonators without the usual caps to ground.  Does that seem to work with reasonable accuracy?

[Reply #2 on:]

WoW!!! Thanks aloott!!!!!!! That really helped!

[Reply #3 on:]

Hi westfw,

  I picked to the ceramic clock mostly for price.  I didn't realize there was a potential issue with not having a ground pin.   

  I would have to compare to a build with a grounded clock to see if it behaved differently. 

  I do know that driving some dc motors, depending on load and weak batteries the system can occasionally lock up.  I got around this issue by using pwm outputs to hbridge and lowering the duty cycle.

  You could take my schematic and change the clock to a 3 pin clock, or I could post one for you if you are not familiar with Eagle.

  Thanks for the coment.
Paul

[Reply #4 on:]

If it's a design you're giving out, or especially selling pre-manned boards, I would vote for having that ground pin hole.  It may work without, but you're probably out of spec on the ideal load capacitance of your oscillator.  And after all, it's harmless if you don't use it yourself.

[Reply #5 on:]

Hi westfw,

  I picked to the ceramic clock mostly for price.  I didn't realize there was a potential issue with not having a ground pin.   

Have a look at this site for low cost low volume parts:
http://taydaelectronics.com/
They have 3 pin 16Mhz ceramic resonators for $0.17 (20Mhz are only $0.08)
Resistors/diodes/Caps are mostly $0.01

--- bill

[Reply #6 on:]

He can make one of the coolest things!!

[Reply #7 on:]

I replaced the 2 pin 16mhz resonator with a 3 pin resonator.
I created an interactive .htm page.  This page has mouser and other supplier links to all the components.  Let me know if you have any comments.
Thanks,
http://atmega.site40.net/ShieldWeeny.htm
Paul

[Reply #8 on:]

Nice!

[Reply #9 on:]

http://atmega.site40.net/ShieldWeeny.htm
Paul

Apparently, this site only works with IE.
What about for those that don't use IE?

--- bill

[Reply #10 on:]

  I corrected the problem.
  It seems to work in Google Chrome and internet Explorer.

  Let me know if it doesn't work in other browsers.

thanks,
Paul

[Reply #11 on:]

Doesn't seem to work using firefox 12.0 for macos (lion.)
DOES work with Safari 5.1.5

[Reply #12 on:]

That sure is a lot of vias you used. Did you use an autorouter? Also see a lot of right angles in your tracks. Not a god idea for noise, but thats just my opinion. Looks good otherwise though

[Reply #13 on:]

  Yes, I used the autorouter.  I'm not sure how to do manual traces so I guess we are kind of stuck.  I also looked at the firefox browser and I'm not sure what's happening there either.
Paul

[Reply #14 on:]

You will need an atmega328 or atmega168 with bootloader flashed, and a CP2102 which is a $3.00 (ebay) usb to serial converter,

I would suggest that you get a real avr programmer and be done with that usb2serial stuff. And you can always reuse your programmer on future project, and no need to buy an avr with bootloader flashed - with your own programmer, you can flash whatever you want.